1. Technical Field
The present invention relates to a wavelength conversion device, an illumination device and a projector.
2. Related Art
Hitherto, there has been known a light source device that performs wavelength conversion on excitation light emitted from a solid-state light source, and emits the converted light as fluorescence (see, for example, JP-A-2011-129354).
The light source device disclosed in JP-A-2011-129354 includes a solid-state light source and a reflection-type fluorescence rotating body. The reflection-type fluorescence rotating body out of these components includes a phosphor layer and a heat dissipation member to which the phosphor layer is fixed by a bonding member. In this phosphor layer, a portion of excitation light emitted from the solid-state light source is converted into light having a wavelength different from that of the excitation light to generate fluorescence.
Incidentally, it is known that, in a case where the temperature of the phosphor layer rises, the wavelength conversion efficiency of light incident from the solid-state light source decreases. Therefore, in a wavelength conversion device such as the reflection-type fluorescence rotating body disclosed in JP-A-2011-129354, a heat dissipation member is rotated, and a phosphor layer formed on the heat dissipation member is cooled.
However, in the wavelength conversion device disclosed in JP-A-2011-129354, since the phosphor layer is formed in the substantially entire region of the heat dissipation member (substrate) on the light incident side, a heat dissipation area for dissipating heat of the phosphor layer is insufficient even in a case where the heat dissipation member is rotated. Therefore, a case may occur in which the temperature of the phosphor layer has a tendency to rise, and the heat of the phosphor layer is not able to be reliably dissipated by the heat dissipation member.
That is, in the wavelength conversion device disclosed in JP-A-2011-129354, the phosphor layer is not able to be cooled to such an extent that a decrease in wavelength conversion efficiency does not occur, and thus there is a problem that a decrease in wavelength conversion efficiency due to the phosphor layer is incurred.